|
|
 |
 |
Collection >
Author >
Author >
Author >
NASA Center >
Publication Year >
>
Subject >
>
Availability Options >
>
Item/Media Type >
|
|
| Note: Start a new navigation search by selecting a link above |
|
|
|
 |
|
|
|
|
|
| |
|
|
|
|
| |
|
| Title: |
Current Sheet Formation in a Conical Theta Pinch Faraday Accelerator with Radio-frequency Assisted Discharge
|
| Author(s): |
Polzin, Kurt A.; Hallock, Ashley K.; Choueiri, Edgar Y.
|
| Abstract: |
Data from an inductive conical theta pinch accelerator are presented to gain insight into the process of inductive current sheet formation in the presence of a preionized background gas produced by a steady-state RF-discharge. The presence of a preionized plasma has been previously shown to allow for current sheet formation at lower discharge voltages and energies than those found in other pulsed inductive accelerator concepts, leading to greater accelerator efficiencies at lower power levels. Time-resolved magnetic probe measurements are obtained for different background pressures and pulse energies to characterize the effects of these parameters on current sheet formation. Indices are defined that describe time-resolved current sheet characteristics, such as the total current owing in the current sheet, the time-integrated total current ('strength'), and current sheet velocity. It is found that for a given electric field strength, maximums in total current, strength, and velocity occur for one particular background pressure. At other pressures, these current sheet indices are considerably smaller. The trends observed in these indices are explained in terms of the principles behind Townsend breakdown that lead to a dependence on the ratio of the electric field to the background pressure. Time-integrated photographic data are also obtained at the same experimental conditions, and qualitatively they compare quite favorably with the time-resolved magnetic field data.
|
| NASA Center: |
Marshall Space Flight Center
|
| Publication Date: |
July 20, 2008
|
| Document Source: |
CASI |
| No Digital Version Available: |
|
| Document ID: |
20090001288
|
| Publication Information: |
Number of Pages = 16 |
| Price Code: |
A03 |
| Meeting Information: |
44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 20 - 23 Jul. 2008, Connecticut, United States |
| Keywords: |
ELECTRIC FIELDS; THETA PINCH; ACCELERATORS; CURRENT SHEETS; INDUCTANCE; RADIO FREQUENCY DISCHARGE; FARADAY EFFECT; ELECTRODELESS DISCHARGES; PULSED INDUCTIVE THRUSTERS; SPACECRAFT PROPULSION; MAGNETIC FIELDS;
|
| Accessibility: |
Unclassified; Copyright; Unlimited; Publicly available; |
| Updated/Added to NTRS: |
2009-01-14 |
|
|
|
